Ground-isolated electromagnetically operated vacuum relay



May 27, 1969 DEAL ET AL 3,447,107

GROUND-ISOLATED ELECTROMAGNETICALLY ()PERATED VACUUM RELAY Filed Dc. 2, 1965 INVENTOR. ROGER L. DEAL BY ROBERT W. HANSON United States Patent 3 447 107 GROUND-ISOLATED ELIlCTROMAGNETICALLY OPERATED VACUUM RELAY Roger L. Deal and Robert W. Hansen, San Jose, Calif.,

assignors to Jennings Radio Manufacturing Corporation, San Jose, Calif., a corporation of Delaware Filed Dec. 2, 1965, Ser. No. 511,106

Int. Cl. H01h 1/66, 51/00 US. Cl. 335-151 8 Claims This invention relates to electromagnetic relays and particularly to a miniaturized vacuum relay in which the high voltage terminals of the relay are electrically isolated from the actuating mechanism therefor which is preferably at ground potential.

The advent of space travel has imposed the necessity of miniaturization of vacuum components which were heretofore not required to be of small size. While reduction in size has solved some problems, it has created other problems, such as attachment of the miniature relay to an actuating mechanism, and the electrical isolation of such actuating mechanism from the high voltage terminals of the relay. Accordingly, it is one of the objects of the invention to provide a composite combination of a miniature vacuum switch and an actuating mechanism therefor which is electrically isolated from the switch.

It is essential for reliable operation of a space capsule in which a relay is used that the relay meet stringent vibration and acceleration requirements. This requirement is usually met by imposing a strong resilient bias on the movable contact of the switch portion of the relay so that contact pressure is maintained at a high value and contact resistance at minimal value. The imposition of such strong resilient bias however creates the problem of providing a small-size electromagnetic actuator of sufficient power to overcome the bias to operate the switch. Accordingly, it is another object of the invention to provide an actuator mechanism for a miniature vacuum switch which possesses exceptional efiiciency and power characteristics in comparison to its size.

Most conventional switches possess contacts resiliently biased in at least one direction. For maximum reliability however it is an advantage that the mobile contact of the switch be resiliently biased in both directions, i.e., whether it is open or closed. Accordingly, it is a still further object of the invention to provide an electromagnetic actuator which affords separate resilient biasing means for each direction of movement of the mobile contact in a miniaturized vacuum switch.

The invention possesses other objects and features of advantage, some of which with the foregoing, will be apparent from the following description and the drawings. It is to be understood however that the invention is not limited by the said description and drawings, but may be embodied in various forms within the scope of the appended claims.

Referring to the drawings:

FIG. 1 is an elevational view, portions of the structure being shown in section to disclose the underlying parts.

FIG. 2 is a view taken in the direction indicated by the arrow 2 in FIG. 1. The outer housing is broken away to show the underlying parts.

FIG. 3 is a plan view.

FIG. 4 is a side elevational view with a portion of the housing broken away to illustrate the manner of displacement of one of the resilient biasing means.

FIG. 5 is a fragmentary view of the pole-piece against which the armature abuts when the electromagnetic actuator is energized.

FIG. 6 is a fragmentary sectional view showing the slidable union between the actuator rod of the switch and the spring arm to which it is connected.

Broadly considered, the relay of the invention comprises a miniature vacuum switch element including an envelope from which an actuator rod extends, with the switch element being rigidly mounted on one end of a sheet-metal housing adapted to support the switch and enclose an electromagnetic actuating assembly. The switch element is electrically isolated from the metallic housing and from the actuating assembly to which it is operatively connected by dielectric means interposed therebetween. Spring means are associated with the electromagnetic actuating assembly to resiliently bias the actuator rod in both directions. To secure adequate power from the electromagnetic assembly to overcome the strong resilient bias imposed on the actuator rod novel means have been provided which increase the efilciency of the electromagnetic actuating assembly while maintaining the requisite small size.

In terms of greater detail, the ground-isolated miniature vacuum relay of the invention comprises a vacuum switch fabricated according to the teaching of application Ser. No. 448,322 filed in the name of Robert W. Hansen, and assigned to the assignee of the instant invention. Briefly, this vacuum switch comprises a pair of axially aligned tubular ceramic members 2 and 3, closed at one end by a terminal member 4 provided with a radially extending terminal lug 6, and closed at its other end by a metallic diaphragm 7 supporting at its mid-point a. conductive actuator rod 8 which extends into the envelope to constitute a movable contact therewithin. The diaphragm is also provided with a radially extending terminal lug 9 for connecting the switch into a circuit. Intermediate the diaphragm 7 and terminal end plate 4 is positioned an annular electrode 11, provided with a radially extending terminal lug 12 as shown. Within the vacuum switch the terminal electrodes 4 and 11 are provided with fixed contacts adapted to be engaged and disengaged by the movable contact upon transverse movement of the actuator movable contact rod 8. The terminal lug 9 is considered a common terminal lead, so that the circuit may be switched between terminal lugs 6-9 and 12-9.

In order to electrically isolate terminal electrode 7 from the actuating mechanism, and to provide a rigid mounting for the switch, the present invention contemplates the interposition of a tubular dielectric spacer 13, preferably ceramic, between the terminal electrode 7 and metallic base palte 14, the latter preferably fabricated from thin gauge sheet metal. The union of terminal member 7 with the tubular ceramic member 13 is brazed so as to insure the permanency of the union despite the most severe impact shocks or acceleration. For the same reason the opposite end of spacer 13 is brazed to base plate 14.

Attached to base plate 14 is cup-shaped hollow housing 16, having an open end 17 and a closed end 18 as shown. The cup-shaped housing is fabricated from sheet-metal and is hermetically secured to the base plate 14 by any suitable means. Adhesives of the epoxy variety are preferred.

Within housing 16, and rigidly supported on base plate 14, is a U-shaped highly permeable magnetic coil frame having a bottom 19, an upper arm 21, and a lower arm 22. The arm 21 is attached to the base plate as by spot welding. A pole piece 23 having a central aperture 24 extends between the free ends of the arms 21 and 22 in substantial parallelism with the bottom 19. A central core 26 is rigidly secured in the bottom 19 and extends freely substantially perpendicular thereto into the aperture 24 in pole piece 23. The ratio of the diameter of aperture 24 to the diameter of the outer free end 27 of the core is proportioned to secure the desired high power characteristics from the solenoid, in a manner which will hereinafter be more fully explained. The solenoid is connected to a source of electric power by leads 28 extending through a suitable aperture 29 formed in the housing 16 as shown.

Supported on the lower arm 22 of the coil frame is an armature 31. The armature is pivoted adjacent one of its ends on the arm 22, and is resiliently biased in a counterclockwise direction as viewed in FIG. 1 with a predetermined force by coil spring 32. Mounted on armature 31 is a non-magnetic resilient spring arm 33. The spring arm 1 extends over the entire length of the armature and is attached thereto as by spot welding the end portion of the spring arm adjacent coil spring 32 to the armature. This union is shown at 34. At its other end the spring arm is provided with an integral flange 35 disposed substantially at right angles to the spring arm. The flange is apertured as shown in FIG. 6 and serves to slidably receive a dielectric sleeve 36, preferably ceramic, which engages the outer free end of actuator rod 8. The sleeve is preferably cemented to the actuator rod. It will thus be seen that the sleeve 36 effectively electrically isolates the actuator rod from the actuating assembly.

From the foregoing it will be understood that the bias imposed by coil spring 32 pivots the armature 31 counterclockwise about the fulcrum provided by coil frame arm 22. The upper end of the armature as viewed in FIG. 1 impinges against the resilient spring arm closely adjacent the point where the resilient spring arm changes direction to provide the angularly disposed flange. Thus, when the armature is biased in this direction, the only resilience in the system is that which imposed by the spring 32. On the other hand, when the actuator is energized, the magnetic field generated by the coil and appearing in the frame and in the annular gap 24 in pole piece 23 attracts the armature into abutting relationship with the pole piece and core.

In conventional solenoids the magnetic circuit is concentrated in a permeable U-shaped coil frame completed only by the armature being brought into abutting relationship with the ends of the coil frame and core. For the applications for which the instant relay is designed such conventional solenoid design has been found to be inadequate. It has been found that a more effective magnetic field, with a consequent increase in the power with which the armature is actuated, is secured when the coil frame is constructed to provide a flat face plate constituting an auxiliary pole piece 23, apertured as shown, extending between the coil frame arms 21 and 22. With this construction an annular space is provided between the free end of the core 27 and the pole piece as shown. The width of the annular space is proportioned to provide a degree of flux density which, in cooperation with the effective area of pole piece 23 and core 26, provides the requisite power to overcome the inordinately strong bias on the actuator rod. Additionally, placement of the aperture in relation to the pivotal axis of the armature is significant in securing the requisite power.

It has been stated that resilient bias is provided in the system in both directions of travel of the actuator rod 8. In the position of the parts shown in FIG. 1, such resilient bias is provided by the coil spring 32. When the armature moves to the right in response to the magnetic field generated by the coil, the actuator rod 8 quickly attains its maximum displacement, determined by the spacing between the fixed and movable contacts. This maximum displacement is attained prior to abutment of the armature with pole piece 23 and core end 27. When this point of maximum displacement of the actuator rod is reached the resilient spring arm 33 flexes about its point of securement to the armature, and the armature pulls away from the unattached upper end of the resilient arm, thus resiliently flexing the arm. With the armature held in abutting relation with the pole piece 23, the spring arm 33 imposes a predetermined resilient bias on the free end of the actuator rod so as to preclude the deleterious effects of vibration, shock and acceleration.

We claim: I

1. An electromagnetically actuated relay comprising:

(a) a vacuum switch including an evacuated envelope enclosing fixed and movable contacts and an actuator rod extending therefrom movable to make or break a circuit through the switch, a portion of said actuator rod within the envelope constitutes said movable contact,

(b) an actuating assembly mounted on said evacuated switch envelope and including a magnetically responsive spring-pressed armature connected to the actuator rod to effect movement thereof to make or break a circuit through the switch, and

(c) dielectric means interposed between the actuating assembly and the switch to electrically isolate one from the other.

2. The relay according to claim 1, in which said dielectric means comprises a tubular dielectric sleeve interposed between the switch and the actuating assembly and a tubular dielectric sleeve interposed between the actuator rod and the armature.

3. The relay according to claim 1, in which said vacuum switch envelope is closed at opposite ends by electrically conductive end caps constituting terminal electrodes and said actuator rod is conductively connected electrically to one of the end caps, the actuator rod being electrically insulated from the armature by a dielectric sleeve supported on the armature and engaging the actuator rod.

4. The relay according to claim 1, in which said actuating assembly includes a high permeability U-shaped coil frame, an auxiliary pole piece connecting the free ends of the U-shaped coil frame, said pole piece having an aperture therethrough, a core supported on the coil frame and extending in a free end into the aperture in the auxiliary pole piece, and a coil about the core within the frame energizable to create a magnetic field in the coil frame and core to effect transverse displacement of the armature.

5. The relay according to claim 1, in which said armature includes a resilient arm secured thereon, one end of said resilient arm being connected to the spring-pressed armature and the other end of the resilient arm being insulatingly connected to the actuator rod so that movement of the spring-pressed armature in one direction effects resilient flexure of the resilient arm to impose a strong resilient bias on the actuator.

6. An electromagnetica'lly actuated relay comprising:

(a) a metallic support plate;

(b) an electromagnetic actuating assembly including a generally U-shaped highly permeable magnetic frame attached to one side of said support plate having an upper arm, a lower arm, and a bottom joining the arms, a center pole piece having one end attached to said frame and extending parallel to said arms, an electrical coil surrounding the pole piece, a highly permeable face plate extend-ing across said coil parallel to said bottom and connected to said arms, said face plate having an aperture therethrough, and said pole piece terminating in a free end extending into the aperture spaced from the face plate to form a gap in the magnetic circuit, and an armature pivot-ally attached to said lower arm and extending across the frame toward said upper arm to pivot about the lower arm into flat abutting relation with said face plate when the coil is energized;

(-c) spring means urging said armature to pivot away from said face plate;

(d) a spring arm having one end attached to said arma- 5 'ture and its other end extending away from the armature toward said support plate;

(e) a switch mounted on the other side of said support plate including a first contact and an electrically conductive contact rod having a portion movable to make or break a circuit with said first contact and having an end connected to the other end of said spring arm to be moved by the armature; and

(f) dielectric means interposed between the switch and said support plate including means between the armature and the rod to electrically isolate the switch from the actuating assembly.

7. The relay of claim 6 wherein said dielectric means includes a tubular dielectric sleeve carried by said spring arm :and fixed to said rod.

8. The relay of claim 6 wherein the switch is arranged with respect to the armature such that the spring arm imposes a strong yieldable bias on the actuator red when said coil is energized.

References Cited UNITED STATES PATENTS BERNARD A. GI'LHEANY, Primary Examiner. ROY N. ENVALL, JR., Assistant Examiner.

U.S. C-l. X.R. 200-144 

1. AN ELECTROMAGNETICALLY ACTUATED RELAY COMPRISING: (A) A VACUUM SWITCH INCLUDING AN EVACUATED ENVELOPE ENCLOSING FIXED AND MOVABLE CONTACTS AND AN ACTUATOR ROD EXTENDING THEREFROM MOVABLE TO MAKE OR BREAK A CIRCUIT THROUGH THE SWITCH, A PORTION OF SAID ACTUATOR ROD WITHIN THE ENVELOPE CONSTITUTES SAID MOVABLE CONTACT, (B) AN ACTUATING ASSEMBLY MOUNTED ON SAID EVACUATED SWITCH ENVELOPE AND INCLUDING A MAGNETICALLY RESPONSIVE SPRING-PRESSED ARMATURE CONNECTED TO THE ACTUATOR ROD TO EFFECT MOVEMENT THEREOF TO MAKE OR BREAK A CIRCUIT THROUGH THE SWITCH, AND (C) DIELECTRIC MEANS INTERPOSED BETWEEN THE ACTUATING ASSEMBLY AND THE SWITCH TO ELECTRICALLY ISOLATE ONE FROM THE OTHER. 